I can see this in my students in my introductory class. You can ask them to calculate a concentration of a solution and they will reply just fine. But when you ask them to go into the lab and actually prepare a solution of a certain concentration you draw blanks in 9 cases out of 10. Students are trained in AP Chemistry to spot problems according to keywords and apply the appropiate formula, but they have never thought about the underlying meaning of the things they do, and they cannot connect different subjects to save their lives.
The mechanical kinesthetics of combining things is not the same skillset as the mathematical process of computing it. Lab work is its own craft.
Based on what you're saying, I'm assuming you already put your questions in the "Story time" format and are getting that 1/10 success rate because the story problems are yet a Third skill - this time one about reading comprehension and language mastery.
Reading comprehension isn't kinesthetics and that's not computation. One may partially inform the other, but each skill is fairly independent.
Being able to go from some constructed story to a math problem is a skill that can be tested elsewhere (and really, should be assumed if someone clearly has proficient enough numeracy to do combinatorics) Questions should be testing one thing as isolated as possible, not the same things repeatedly.